1. Field of the Invention
The present invention relates to a heat dissipation structure for an optical engine, and more particularly, to a heat dissipation structure for an optical engine with a reflective light valve.
2. Description of the Prior Art
Please refer to FIG. 1, which shows a conventional optical engine 10. Generally, a projection device with digital light processing (DLP) technology has an optical engine 10. The optical engine 10 includes a light source 12, an optical main body 14 and a projection lens 16. The light source 12 generates an incident light beam 17, and the optical main body 14 processes the incident light beam 17 to become an image light beam 18, and then the image light beam 18 is projected through the projection lens 16 for forming an image.
The optical main body 14 includes a light-filtering module 20, a digital micro-mirror device (DMD) 22 and a case 24. The light-filtering module 20 filters the incident light beam 17 to have a specific color and be projected on the DMD 22. The DMD 22 is an important device with a great number of rotatable micro-mirrors and receives data represented by electronic signals. The angle of each micro-mirror is controlled by current for reflecting an incident light beam 17 to become an image light beam 18 or a dumped light beam 26. The dumped light beam 17 is projected on the case 24 but not into the projection lens 16.
Heat comes from at least three aspects to the DMD 22: the radiation heat from the incident light beam 17, the heat generated by DMD 22 itself while in operation, and the parasitic heat conducted from the optical engine 10 or other components in the projection device. The main source of the parasitic heat is the radiation heat from the incident light beam 17 that is absorbed by the case 24. The cooling of the DMD 22 is good or not directly affects the durability and lifetime of the DMD 22. Thus, conventionally a heat sink 28 is attached on the rear surface of the DMD 22 for cooling in order to lower the temperature of the DMD 22.
While the demand for higher brightness of the projection device increases, the light source 12 must have a high lumen in brightness. However, more heat is generated and the DMD 22 with the conventional cooling method cannot withstand such heat. Therefore, the cooling of the DMD 22 must be improved.